package com.other;

import java.math.BigInteger;
import java.util.Date;
import java.util.Random;
import java.util.zip.CRC32;

/**
 * Created by baiguantao on 2017/6/20.
 * 适用于17以下的版本吧
 */
public class KeyGenerator {

        /**
         * @param s
         * @param i
         * @param bytes
         * @return
         */
        public static short getCRC(String s, int i, byte bytes[])
        {
            CRC32 crc32 = new CRC32();
            if (s != null)
            {
                for (int j = 0; j < s.length(); j++)
                {
                    char c = s.charAt(j);
                    crc32.update(c);
                }
            }
            crc32.update(i);
            crc32.update(i >> 8);
            crc32.update(i >> 16);
            crc32.update(i >> 24);
            for (int k = 0; k < bytes.length - 2; k++)
            {
                byte byte0 = bytes[k];
                crc32.update(byte0);
            }
            return (short) (int) crc32.getValue();
        }

        /**
         * @param biginteger
         * @return String
         */
        public static String encodeGroups(BigInteger biginteger)
        {
            BigInteger beginner1 = BigInteger.valueOf(0x39aa400L);
            StringBuilder sb = new StringBuilder();
            for (int i = 0; biginteger.compareTo(BigInteger.ZERO) != 0; i++)
            {
                int j = biginteger.mod(beginner1).intValue();
                String s1 = encodeGroup(j);
                if (i > 0)
                {
                    sb.append("-");
                }
                sb.append(s1);
                biginteger = biginteger.divide(beginner1);
            }
            return sb.toString();
        }

        /**
         * @param i
         * @return
         */
        public static String encodeGroup(int i)
        {
            StringBuilder sb = new StringBuilder();
            for (int j = 0; j < 5; j++)
            {
                int k = i % 36;
                char c;
                if (k < 10)
                {
                    c = (char) (48 + k);
                }
                else
                {
                    c = (char) ((65 + k) - 10);
                }
                sb.append(c);
                i /= 36;
            }
            return sb.toString();
        }

        /**
         * @param name
         * @param days
         * @param id
         * @param prtype
         * @return
         */
        public static String MakeKey(String name, int days, int id)
        {
            id %= 100000;
            byte bkey[] = new byte[12];
            bkey[0] = (byte) 1; // Product type: IntelliJ IDEA is 1
            bkey[1] = 14; // version
            Date d = new Date();
            long ld = (d.getTime() >> 16);
            bkey[2] = (byte) (ld & 255);
            bkey[3] = (byte) ((ld >> 8) & 255);
            bkey[4] = (byte) ((ld >> 16) & 255);
            bkey[5] = (byte) ((ld >> 24) & 255);
            days &= 0xffff;
            bkey[6] = (byte) (days & 255);
            bkey[7] = (byte) ((days >> 8) & 255);
            bkey[8] = 105;
            bkey[9] = -59;
            bkey[10] = 0;
            bkey[11] = 0;
            int w = getCRC(name, id % 100000, bkey);
            bkey[10] = (byte) (w & 255);
            bkey[11] = (byte) ((w >> 8) & 255);
            BigInteger pow = new BigInteger("89126272330128007543578052027888001981", 10);
            BigInteger mod = new BigInteger("86f71688cdd2612ca117d1f54bdae029", 16);
            BigInteger k0 = new BigInteger(bkey);
            BigInteger k1 = k0.modPow(pow, mod);
            String s0 = Integer.toString(id);
            String sz = "0";
            while (s0.length() != 5)
            {
                s0 = sz.concat(s0);
            }
            s0 = s0.concat("-");
            String s1 = encodeGroups(k1);
            s0 = s0.concat(s1);
            return s0;
        }
    public static void main(String[] args)
    {
        KeyGenerator keyGenerator = new KeyGenerator();
        String name = "Gurkan CAKIR";

        Random r = new Random();
        System.out.println(keyGenerator.MakeKey(name, 0, r.nextInt(100000)));
    }
}
